An injunction keeps activists away from Shell rigs, but they've got some new tricks.

SEATTLE — One day last week, guests from various engineering and shipping companies around Seattle were invited to a reception at the Space Needle, supposedly hosted by Royal Dutch Shell to celebrate the upcoming debut of offshore oil drilling in the Arctic Ocean.

But most of the guests, it turned out, were actors and activists merely posing as drilling enthusiasts.

They looked on in mock horror as a giant ice sculpture emblazoned with Shell's corporate logo began spraying a stream of Diet Coke on an elderly woman who was the supposed guest of honor. The woman, who gained fame last year when she was pepper-sprayed by police at an Occupy Seattle protest, shrieked as the emcees grabbed stuffed polar bears to help mop up the spill.

A video of the ensuing chaos quickly gained half a million views on YouTube.

By the next day, media staff from Greenpeace and the Yes Men, who had staged the prank, were set up in a conference room at a Seattle hotel. They fielded calls from confused reporters as a live Twitter feed of the #shellfail prank played across a large screen on the wall.

In another era, anti-drilling activists would have been out at sea, stringing banners from Shell's drilling rigs and swooping in their boats among the Shell vessels poised to steam out of Seattle toward the Arctic.

But this is the age of new media, when a video is worth a thousand ships. It also comes as Shell has launched an unusual preemptive legal strike that has foreclosed many traditional protest options against an exploration program that could open an entirely new energy frontier in the U.S. Arctic.

The preliminary injunction issued by U.S. District Judge Sharon Gleason in response to a flood of motions by Shell requires Greenpeace to stay at least a kilometer away from Shell's two Arctic drilling rigs, the Kulluk and the Noble Discoverer, and half a kilometer from accompanying Shell support vessels.

The upshot is that while Greenpeace may once have faced a trespassing charge or some minor equivalent for harassing Shell's drilling fleet, the organization now faces the much harsher penalties associated with violating a federal injunction if activists stray past the boundaries.

"Certainly this injunction we are faced with demanded some new thinking, and I guess the tactics needed to counter an international oil campaign have to be creative," Greenpeace USA spokesman James Turner said. "Social media offers us the opportunity to use humor and inventiveness to reach people in a way that hopefully entertains and engages them, while making a serious point at the same time."

For the more serious work, Greenpeace has moored its 236-foot ice-class ship, the Esperanza, a few miles from Seattle in preparation for steaming north with -- but not too near -- what activists like to call Shell's "armada."

From the Esperanza, conservationists hope to monitor drilling's possible impact on wildlife such as polar bears, walrus and bowhead whales. Shell already has been required to minimize any effects.

The ship has been equipped with a pair of small research submarines, provided by the La Jolla-based Waitt Institute, that will be deployed not for harassment but to begin methodical mapping via high-definition video the virtually unknown terrain of the Chukchi Sea, one of the most remote oceans on Earth.

"We're going to be diving down into places where no man or woman has ever been before," Jackie Dragon, lead campaigner for Greenpeace's Arctic tour, said in an interview on the Esperanza.

Greenpeace will also be fielding an unmanned aerial vehicle that will shoot photos from above.

"We basically have our own little drone," said Dan Howells, Greenpeace USA's deputy campaigns director. "The idea is to get ourselves into position to be the eyes of the world on these operations."

The no-protest-zone court orders apply only to Greenpeace, whose activists earlier this year boarded and chained themselves to Shell's Noble Discoverer offshore drilling rig when it was docked in New Zealand for renovations before its long trip to the Arctic.

But a flurry of separate court actions filed by Shell targeting many of the nation's biggest environmental groups had an even more important effect. By getting court review of the drilling plans started early, Shell effectively undermined opponents' ability to halt drilling by filing a last-minute lawsuit and obtaining a court injunction, analysts say.

Shell officials say they simply want to get a court ruling early on issues they know they'll be sued over eventually.

"We view this very much as not trying to subvert anybody's rights to litigate ... but we would like to control the timing of it," said Pete Slaiby, vice president for Shell Alaska.

While the lawsuits wind their way through court, other environmental groups have joined Greenpeace to raise a voice of dissent.

The Alaska Wilderness League has sponsored what it bills as polar bear dance parties and a rally at the White House, delivering the signatures of more than 1 million people opposed to oil development in the offshore Arctic. The organization is hoping to schedule a series of vigils over the next few weeks in remote Eskimo communities that could be devastated by an oil spill.

"Until we hear that the [drilling permits] are final, we're going to push our members to make those calls," said Leah Donahey, western Arctic and oceans program director for the group.

Shell, for its part, didn't have much of a response to Greenpeace's renegade video.

"We're in a ramp-up period right now, with our oil spill response training and bringing new jobs on," said company spokeswoman Kelly op de Weegh. "We're focused mostly on a responsible exploration program this summer."